[Bugfix][Rust Frontend][Renderer] Align DeepSeek tool-call arguments with deepseek-recipe (#56260)
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com> Co-authored-by: Bugen Zhao <i@bugenzhao.com> Co-authored-by: Codex <noreply@openai.com> Signed-off-by: JinYan Su <751080330@qq.com> Signed-off-by: Bugen Zhao <i@bugenzhao.com>
JinYan Su committed
Sep 11, 2026 at 18:19 UTC
79c137c6ada6bf9384e14feb260e10d91bf58c0b
2 files changed
+57
-12
rust/src/chat/src/renderer/deepseek.rs
+11
-12
@@ -11,7 +11,7 @@ use std::collections::HashMap;
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use std::fmt::Write as _;
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use serde::Serialize;
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-use serde_json::Value;
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+use serde_json::{Map, Value};
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use serde_json_fmt::JsonFormat;
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use llm_multimodal::DEEPSEEK_V41_IMAGE_PLACEHOLDER;
@@ -685,19 +685,18 @@ fn encode_arguments_to_dsml(
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dialect: DsDialect,
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) -> Result<()> {
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let parameter_tag = dialect.parameter_tag();
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- let arguments: Value = serde_json::from_str(&tool_call.arguments).map_err(|error| {
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- Error::ChatTemplate(format!(
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- "assistant tool call has invalid JSON arguments for DeepSeek: {error}"
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- ))
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- })?;
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- let Some(arguments) = arguments.as_object() else {
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- return Err(Error::ChatTemplate(
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- "assistant tool call arguments for DeepSeek must be a JSON object".to_string(),
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- ));
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- };
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+ // Match deepseek-recipe's render_tool_arguments for both V4 and V4.1:
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+ // https://github.com/deepseek-ai/deepseek-recipe/blob/8cadfede7063c896b944e7bae05daa3549ae97ea/deepseek-recipe-encoding/src/v4/mod.rs#L48-L58
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+ let arguments = serde_json::from_str::<Map<String, Value>>(&tool_call.arguments)
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+ .unwrap_or_else(|_| {
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+ Map::from_iter([(
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+ "arguments".to_owned(),
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+ Value::String(tool_call.arguments.clone()),
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+ )])
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+ });
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let mut wrote_parameter = false;
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- for (key, value) in arguments {
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+ for (key, value) in &arguments {
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if wrote_parameter {
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out.push('\n');
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}
rust/src/chat/src/renderer/deepseek_v4/tests.rs
+46
@@ -9,6 +9,7 @@ use serde_json::Value;
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use super::DeepSeekV4ChatRenderer;
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use crate::ChatRenderer;
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use crate::event::{AssistantContentBlock, AssistantToolCall};
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+use crate::renderer::deepseek_v41::DeepSeekV41ChatRenderer;
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use crate::renderer::test_utils::{FixtureRequestOptions, fixture_chat_request};
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use crate::request::{ChatMessage, ChatRequest, ChatTool, GenerationPromptMode, ReasoningEffort};
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@@ -399,6 +400,51 @@ fn reasoning_effort_template_kwarg_is_ignored() {
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assert!(rendered.ends_with("<｜Assistant｜><think>"));
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}
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+#[test]
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+fn tool_call_arguments_preserve_non_objects_like_recipe() {
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+ let renderers: [(&dyn ChatRenderer, &str); 2] = [
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+ (&DeepSeekV4ChatRenderer::new(), "parameter"),
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+ (&DeepSeekV41ChatRenderer::new(), " parameter"),
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+ ];
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+ for arguments in [
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+ "not json",
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+ "[1, 2]",
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+ "null",
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+ "42",
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+ "true",
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+ "",
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+ r#""text""#,
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+ r#""{\"query\":\"double\"}""#,
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+ ] {
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+ let request = ChatRequest {
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+ messages: vec![
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+ ChatMessage::assistant_blocks(vec![AssistantContentBlock::ToolCall(
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+ AssistantToolCall {
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+ id: "call".to_string(),
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+ name: "search".to_string(),
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+ arguments: arguments.to_string(),
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+ },
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+ )]),
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+ ChatMessage::tool_response("result", "call"),
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+ ],
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+ ..ChatRequest::for_test()
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+ };
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+
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+ for (renderer, tag) in renderers {
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+ let prompt = renderer.render(&request).unwrap().prompt.into_text().unwrap();
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+ let parameters: Vec<_> =
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+ prompt.lines().filter(|line| line.contains("parameter name=")).collect();
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+ assert_eq!(
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+ parameters,
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+ [format!(
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+ "<｜DSML｜{tag} name=\"arguments\" string=\"true\">{arguments}</｜DSML｜{tag}>"
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+ )],
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+ "arguments: {arguments:?}, tag: {tag:?}",
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+ );
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+ }
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+ }
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+}
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+
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#[test]
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fn tool_results_are_sorted_by_previous_assistant_tool_call_order() {
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let mut request = ChatRequest {